Pastry: Sift flour and salt into a bowl, rub in butter, add egg yolk and lemon juice and mix to a firm dough. Cover and refrigerate 20 minutes.
Roll dough out large enough to line a 25cm flan tin, trim the edges.
Cover pastry with greaseproof paper and fill with dried beans or rice to hold in shape while cooking. Bake in a moderate oven for 7 minutes, remove paper and beans and bake a further 7 minutes. Set aside until required.
# Whisk eggs, cream, milk and cheeses together and set aside.
Slice spring onions.
Spread flaked salmon and spring onions evenly over pastry. Pour over egg mixture and sprinkle with paprika. Bake in a moderate oven for about 30 minutes or until set.